Scale.



C. H. LITTLE.

SCALE.

APPLICATION FILED FEB. 2|. I916.

Patented July 30, 1918.

hue/(barf CHARLES H. LITTLE, OF EAST CLEVELAND, OHIO.

SCALE.

Specification of Letters Patent.

Patented July 30, 1918.

Application filed February 21, 1916. Serial No. 79,493.

To all whom it may concern:

Be it known that I, CHARLES H. LITTLE, a citizen of the United States, residing at East Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Scales, of which the following is a full, clear, and exact description.

This invention relates to scales and rulers, and particularly to metal scales and rulers. The invention has particular utility also in circular scales or protractors.

It is customary to provide wooden rulers with celluloid strips in which graduations and designating characters are cut, so that the ruler can be easily read, the strips of celluloid being cemented to the ruler body. On the other hand, metal rulers and scales usually have graduations and characters out directly in the metal, for while it is reco nized that it would be desirable to provide graduations in celluloid applied to the metal body this is not done because the shrinking tendency of celluloid precludes it being effectively cemented to the metal. Celluloid undergoes a constant shrinkage, and the stresses due to this shrinkage are so great that no known cement can withstand the shrinking tendency of the celluloid, the result being that in time the cemented strip pulls itself loose from the metal. Not only has it been found impossible to permanently secure celluloid strips to metal by cementing, but as far as I am aware no other successful method has been devised, the inevitable result having been that the celluloid in time pulls itself away from the metal and becomes loosened or warps out of shape, causing the ruler to be rendered worthless or its accuracy to be destroyed.

In consequence, although metal rulers and scales have numerous advantages over those formed of wood, among which might be mentioned the non-warping quality of the former, nevertheless metal rulers and scales have not been used to any great extent except in special cases where metal is required, because of the fact that they are difficult to read, especially in poor light, and even in good light they cause a strain on the eyes of the user.

By the present invention I am enabled to effectively and permanently apply a celluloid strip to a metal scale or ruler body without danger of the strip becoming loose at any point and without liability of the accuracy of the tool being destroyed or adversely affected. In other words, I am enabled to attach or anchor a strip such as celluloid to the metal body in a manner such that the shrinking tendency of the celluloid is entirely overcome or at least rcndered ineffective for destroying the accuracy of the device.

In one of its aspects the invention relates to or has particular utility in circular scales or protractors in which, due to the particular shape of the metal body and the manner in which the non-metallic strip is applied and held thereto. the shrinking action of the strip if formed of celluloid or other matcrial having like properties tends to increase rathcr than decrease the binding or holding action between the strip and metal. Other features of my invention, while of importance in circular scales or protractors, may be used to advantage in straight metal rulers.

The invention may be briefly summarized as consisting in certain novel details of const-ruction and combinations and arrangements of parts which will be described in the specification and set forth in the ap-' pended claims.

In the accompanying sheet of drawings wherein I have shown several embodiments of my invention applied to protractors, Figure 1 is a top plan view of the protractor; Fig. 2 is a transverse sectional view on an enlarged scale through some point of the protractor such for example as along the line 2-2 of Fig. 1; Fig. 3 is a similar view showing a modification; Fig. 4 is a perspective view of a portion of the protractor showing a further modification; and Fig. 5 is a view showing on a much enlarged scale the perforations in the base to which the celluloid is applied and the manner in which the perforations are filled with the celluloid.

The scale or protractor includes a metal body 10 which as here shown is in the form of a circle, and in cross-section is substantially in the form of an 101' I-beam. It is not essential that the body 10 be in the form of a complete circle as the same results are obtained if the body is slightly less than a full circle or annulus, the latter being the form in which the invention has been embodied with success.

This body 10 is preferably punched or cut though the latter is provided simply on one groove, and while the strip preferably fill the entire groove, it is not so. essential that s to provide small numerous closely spaced perforations and to cause the innersurface -of the strip to embed itself in and fill these perforations.

wherein the base or web 10 is provided with perforations l0 which are filled with the.

.nonsmetallic strip 11 preferably of cellu 4 which are cut the scale graduations.

from flat metal. into the circular shape and -j act substantially radially so that the tend the arc-shaped strip or annulus thus formed is then provided on 'both sides with slots or grooves 10 and 10", leaving at the inner:

periphery of the strip or body an enlarge-l mentor rim 10, at its outer periphery a substantially similar enlargement or rim 10%". and a connecting web or relatively thin base 10 for the celluloid strip. This provides a' protractor body which is not heavy and at the same time it has sufficient strength to? easily avoid deformation due, to the shrink ing tendency of the celluloid strip even part or one side of the body. I

The upper grooveor slot 1O receives a loid along the inner marginal portion 0' It i. important that the inner marginal edge of the strip 11 engage the shoulder 1O formec at the inner marginal edge of the groove 10 when the strip is first placed in the it tightly engage at its outer marginal edge the outer peripheral part of the groove, for the reason that the shrinkage of the strip" has a tendency to contract the strip and to cause it to bind allthe more firmly against the shoulder 10 ably slightly undercut, as shown in Figs. 2, 3 and 4, While at the outer periphery of -the groove the strip 11 and metal body 10 are dove-tailed, as shown at 1.0-, the groove 10 having a reentrant groove or slot which receives a relatively thin flange provided at the outer peripheral edge of the strip.

Vith the above construction wherein the celluloid strip is embedded or inlaid in the circular groove with the inner edge of the strip bearing against the shoulder formed at theinner peripheral edge of the groove,

and with the graduations provided at the able solvent such as acetone.

inner periphery of the strip next to said shoulder, the shrinkage stresses of the celluloid do not affect the accuracy of the instrument. nor distortor warp the strip.

' Additionally, if desired, thestrip may be cemented in the groove of theinetal body. The use of cement or other fastening means such as hereafter specified is not essential for the reason that the shrinkage stresses at any point of the circular celluloid strip This shoulder is preferzlfency of the shrinkage is to cause the strip to bind all the-inore firmly against the ilshoulder against which the inner edge of thestrip bears.

This shoulder, of course, resists inward contraction of the strip, so that the cement is largely relieved of the shrinking stresses. In consequence, the strip not only stays in position in the groove but its accuracy is never destroyed or ad versely afiected'du'e to the fact that the graduations are at theinner peripheral porder against contraction or dtformation,

Instead of or in addition to the cementl nay employ other methods of-anchoring the strip to the metal body which are; efficient 11 d may be efiiciently employed in straight as well as circular scales or protractors. One expedient which I have employed to advantage consists in positively interlock. ng the strip and netal in the base of the groove at uniformly distributed points roughout the length and breadth of the trip, and the preferred way ofdoing this This is shown in Fig. 3

celluloid. The celluloid an, be forced down into these perforations so as to tightly fill the same by warming the strip before it is placed in the protractor or ruler and then by applying pressure onto the strip. This provides an exceedingly effective anchoring meansbetween the strip and metal body and this istrue particularly if the web is punched from its lower side. The, tendency of the punch or punches is to provide. perforations which are somewhat larger at the bottom of the web than at the top surfaceoand tov leave a bur projecting up from the upper surface of the web,

as is illustrated in the exaggerated or very.

much enlarged view of In consequence, when the strip-1s in position on the metal body with the perforations filled with the celluloid each celluloid filler or plug has at its lower: end an enlarged head which cannot easily ration. l r

It is not essential that the perforations be provided directly-in the base orweb 10? of the bodyi10, for I find that a. separ-ate perforated metalanchor-strigp .152 placed in tion of the strip which is held by the shoul-.

be pulledthrough the per-fo the slot or groove receiving thenonrinetallic.

orcelluloid strip 11 can-be employed as shown in Fig. 4. This metal striplniay be attached to the celluloid strip 11 before the two areplaced in the groove of the body 1O or themetal strip may be placedin the groove, andsecured therein befOlfe the cellue loid strip is applied and anchored thereto.

It desired, the perforated strip 12 may be embedded in the celluloid strip or fastened between two sheets of celluloid, in which event the celluloid of both strips will fill the perforations.

WVith both the constructions shown in Figs. 3 and -it the celluloid strip and perforated web 10 or perforated metal strip .12 may be cemented together. By cementing the parts as well as interlocking them in the manner shown in Figs. 3 and at, the celluloid strip is all the more securely fastened in position.

Having thus described my invention, what I claim is:-

1. In a device of the character described, a metal body having a circular groove and a shoulder at the inner periphery of the groove, and a non-metallic strip bearing graduations seated in said groove and having its inner edge bearing against said shoulder.

"2. In a device of the character described, a metal body having an arcuate groove with av shoulder at its inner periphery and a celluloid strip bearing graduations held in said groove with its inner edge bearing against the shoulder.

23. In a device of the character described, a metal body having a circular or arcuate groove with a shoulder at its inner periphery and a non-metallic strip bearing graduations secured at its under surface to the base of the. groove and at its inner edge hearing against the shoulder.

'1. In a device of the character described, a. metal body having a circular groove with a shoulder at its inner edge or periphery, a celluloid strip in said groove and lnwing its inner edge bearing against said shoulder, said strip having its inner portion next to said shoulder provided with graduations.

5. In a device of the character described, a metal body provided with a circular shoulder, a circular celluloid strip bearing graduations carried by said body and having its inner edge bearing against said shoulder.

6. In a device of the character described, a metal body having a pair of concentric circular shoulders, a circular celluloid strip carried by said body between said shoulders and at. its inner edge bearing against the inner shoulder.

7. In a scale or ruler, a celluloid strip bearing g-aduations, and a metal base to which the strip is attached, the base being provided with perforations filled with celluloid.

S. In a metal scale or ruler body, a graduated celluloid strip attached to said metal body, the adjacent surface ol. the has and strip being interlocked by sockets or peri'orations in one and projections in the other extending into or filling the sockets or perforations.

9. A scale or ruler having a metal body provided with a pair of shoulders, a graduated celluloid strip attached to the body be tween the shoulders, the engaging surfaces of the strip and body at distributed points having intertitting parts which anchor the strip to the body.

10. In a scale or ruler, a metal body having a circular shoulder, a graduated celluloid stri attached to said body and having an inner circular edge bearing against the shoulder, the strip and metal body being fastened together at. nun'ierous closely spaced points by one part having sockets or perforations lilled bv the material ol' the other member.

'11. In a scale or ruler, a metal body ha\ ing a circular groove with an abrupt shoulder at the inner periphery thereof, a circular graduated celluloid strip in said groove and having its inner edge bearing against said shoulder, the base of the groove having sockets lilled with the celluloid ol the strip.

12. In a scale, a metal body having a graduated celluloid strip and having means for mechanically holding the strip against independent shrinkage.

13. In a protractor, a metal body having an annular graduated celluloid strip and having means for mechanically holding the strip against independent shrinkage, said strip having the gradnations provided along its inner periphery.

In testimonv whereof, I hereunto allix my signature.

CHARLES H. LITTLE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, .D. G. 

